Usagi, after failing to hit or catch any balls during softball practice, is shocked that Seiya has so willingly agreed to Sonoko's offer to play a game of softball against her.

Sonoko, the leader of the Tenth Street High's softball team and the most popular sempai in school, is disgusted that Seiya has chosen to hang out with a dimwitted girl like Usagi. She, along with the rest of her fan club, challenge Seiya to a softball match. Should Usagi win, Seiya can continue his relationship with Usagi, however, should Sonoko win, Seiya can no longer speak to Usagi.

From Episode 187 - "Kagayaku Hoshi no Power! Chibi Chibi no Henshin" (The power of the glittering stars! Chibichibi's transformation).